Levothyroxine and the price of a daily pill

In February 2015, retail pharmacies paid an average of 38.4 cents for a generic 50 mcg levothyroxine tablet, the highest monthly figure in the federal government's drug cost survey since the series began in late 2013, according to CMS NADAC data². In October 2026, the latest weekly files⁴ put the same tablet at 4.0 cents.

A daily pill turns small unit prices into real money. At the February 2015 rate, 365 tablets cost a pharmacy $139.99 in ingredient cost. At the October 2026 rate they cost $14.75, almost 90 percent less.

Levothyroxine, a thyroid hormone replacement, is usually prescribed for long-term use, which makes it a good test of what the national acquisition cost does and does not tell a patient. GxRadar analyzed CMS NADAC files through October 2026 for the 50 mcg tablet. The record shows a rise in 2014, a slow decline for six years, and a steep fall from 2021 to 2023. It also shows how far a pharmacy's cost can sit from the amount on a patient's receipt.

Twelve years of NADAC for one strength

Each figure below is GxRadar's monthly median of the weekly NADAC per-tablet rate for generic-classified levothyroxine 50 mcg tablets. The 90-tablet and 365-tablet columns are simple multiplication. The full monthly series is on our levothyroxine page.

The rise came quickly. The monthly figure went from 22.7 cents in November 2013 to 38.4 cents in February 2015, a 69 percent increase. The biggest jumps came in June and July 2014, up 18 percent and 16 percent, in the 2014 files¹. Levothyroxine came up at the time. In written testimony for a November 2014 Senate subcommittee hearing⁸ on generic price increases, a national pharmacists' group said levothyroxine was among the generics most frequently cited in its January 2014 member survey on price spikes, which drew responses from more than 1,000 members.

From 2015 to 2020 the price slipped by a few cents a year. Then it fell fast. Between October 2020 and October 2023 the figure dropped from 24.2 cents to 6.4 cents, according to the 2023 files³. Since 2024 it has stayed between about 4 and 7 cents. CMS has calculated monthly generic rates as a three-month moving average since December 2024, according to its NADAC methodology⁵, which smooths the latest months.

The arithmetic of a year's supply

Here is the year-supply calculation spelled out, using the 2014 average as the baseline so that a single unusual month does not drive the comparison.

A pharmacy filling 365 of these tablets in October 2026 paid its supplier, on average, about $98 less in ingredient cost than it would have at 2014 prices. At the 2026 rate, a 90-tablet fill works out to $3.64 in ingredient cost. Those figures cover only the tablets.

Why levothyroxine is a special case at FDA

Levothyroxine has an unusual regulatory history. On Aug. 14, 1997, FDA announced in the Federal Register⁷ that orally administered levothyroxine sodium products were new drugs and that manufacturers who wanted to keep selling them had to obtain approved new drug applications. The agency cited "significant stability and potency problems," and wrote that since 1991 there had been "no less than 10 firm-initiated recalls of levothyroxine sodium tablets involving 150 lots and more than 100 million tablets." The notice described levothyroxine as having a narrow therapeutic index and gave manufacturers until Aug. 14, 2000.

That history still shapes the market. GxRadar's count of FDA's Drugs@FDA data⁹ found seven NDAs and nine ANDAs whose original approval included a 0.05 mg levothyroxine sodium tablet. Six of the NDAs and seven of the ANDAs still list that strength as marketed. Seven of the nine ANDAs were approved from 2019 through 2026, two in 2019, one in 2020, two in 2022, one in 2023 and one in 2026. The fastest part of the NADAC decline, 2021 to 2023, overlaps that run of approvals. Our data show the overlap. They do not show which products were selling, or in what volume.

FDA's Orange Book¹⁰ lists which levothyroxine products the agency rates as therapeutically equivalent to one another, using codes explained in our guide to therapeutic equivalence codes. Questions about whether a particular product can be substituted belong with a pharmacist or prescriber.

Why NADAC is not the patient price

NADAC is an average of invoice prices that a sample of chain and independent retail pharmacies pay their suppliers, according to the CMS methodology⁵. It covers the drug ingredient only. Discounts and rebates that do not appear on the invoice line are not factored in. The pharmacy's own costs of filling the prescription are outside it entirely.

Medicaid shows how the pieces fit. Federal rules define a professional dispensing fee¹¹ as the fee that "pays for costs in excess of the ingredient cost" each time a drug is dispensed, including a pharmacist's time checking coverage, reviewing drug use, filling the container and counseling the patient. Under 42 CFR 447.512¹², state Medicaid payments for drugs without a federal upper limit must not exceed, in the aggregate, the lower of actual acquisition cost plus that dispensing fee, or the pharmacy's usual and customary charge to the public. Multiple-source drugs that do have a federal upper limit face an aggregate cap based on that limit instead.

Outside Medicaid, the patient's share depends on things NADAC does not measure. A commercial or Medicare Part D plan sets the copay or coinsurance and the deductible. A patient paying cash pays whatever the pharmacy charges, which can be well above or close to its acquisition cost. Our guides on how pharmacies get paid, when the cash price beats the copay and 90-day supplies go through those cases, and our script for talking to your pharmacist suggests ways to ask about price.

The $14.75 figure describes one part of the cost. It is the federal estimate of what a typical retail pharmacy paid for the tablets alone, averaged across the survey. For the same pattern in a drug with dozens of generic makers, see what pharmacies paid for atorvastatin. For drugs moving the other way, see the generics that cost more than in 2014.

CMS posts the monthly NADAC file on the first Monday on or after the 15th, according to the NADAC page on Medicaid.gov⁶, which says the data are also updated weekly. The next monthly file is due Monday, Nov. 16, 2026.